Abstract
Purpose :
Ocular inflammation is associated with progression of retinal degenerative diseases, including AMD (Age-related Macular Degeneration), DR (diabetic retinopathy), and glaucoma. Understanding inflammatory regulation in the context of the immune-privileged retina will lead to novel treatments for chronic inflammation-associated retinal degeneration. We have observed high expression of the inflammatory regulator TRAF3 (tumor necrosis factor receptor-associated factor 3) the murine retina. Objectives for this project include characterization of retinal Traf3 expression and assessment of retinal-Traf3 deficiency on the retinal immune response following optic nerve crush (ONC) injury.
Methods :
Neural retinal (NR)-Traf3 KO mice were generated by Chx10-mediated Cre-recombination of Traf3flox/flox mice (provided by Gail Bishop, U. Iowa). Traf3 deletion efficiency on TRAF3 protein level was assessed by Western blot and immunohistochemistry of mouse retinal tissue sections. A damage-associated immune challenge was induced using the optic nerve crush (ONC) injury procedure. Retinal ganglion cell (RGC) death was observed by retinal tissue whole mount staining with RGC-specific markers RBPMS (RNA binding protein mRNA processing factor) or Brn3a (Brain-3A; POU4F1). The effects of NR-Traf3 deletion on immune-associated RNA transcript expression was measured and analyzed using NanoString technology and nSolver software, respectively.
Results :
TRAF3 protein is highly expressed in neuroretina and NR-specific deletion of Traf3 results in ~62% reduction of TRAF3 in whole retinal lysates. All animals showed RGC loss after 1-week post-ONC; however, the percent RGC loss in NR-Traf3 KO mice was significantly greater (WT: 57.2% vs. KO: 80.4%) and suggests that NR-Traf3 KO mice are more susceptible to ONC-injury. Analysis of retinal tissue mRNA transcripts showed a Traf3-dependent reduction in Immune Response and Cell Surface gene sets, and ONC injury exaggerated this reduction in NR-Traf3 animals.
Conclusions :
Our results support that the major role of Traf3 function in retinal tissue is to promote retinal immune responses. Our work suggests that Traf3 may serve as a novel therapeutic target for treatment of retinal inflammatory disease. Future studies will focus on identifying specific Traf3-dependent immune receptor pathways and investigating mechanistic interactions between Traf3 and retinal inflammatory molecular regulators.
This is a 2020 ARVO Annual Meeting abstract.